1. Field of the Invention
The invention relates to forehead pads. These pads can be used with a respiratory mask for Non-invasive Positive Pressure Ventilation (NPPV) treatment of Sleep Disordered Breathing (SDB).
2. Background of the Invention
Nasal masks are commonly used in the treatment of respiratory conditions and sleep disorders by delivering a flow of breathable gas to a user to either assist the user in respiration or to provide a therapeutic form of gas to the user to prevent sleep disorders such as obstructive sleep apnea (OSA). These nasal masks typically receive a gas through a supply line, which delivers the gas into a chamber formed by walls of the mask.
The mask is generally semi-rigid and has a face portion that is in communication with the nose and/or mouth of a user. The mask is normally secured to the user's head by straps. The straps are adjusted to pull the mask against the face with sufficient force to achieve a gas-tight seal between the mask and the user's face. Gas is thus delivered to the mask through the aperture to the user's nasal passages and/or mouth.
One of the problems that arises with the use of the mask is that in order for the straps to be tight, the mask is compressed against the user's face and may push unduly hard on the user's nose. Additionally the mask may move around on the user's face. Therefore, masks often contain a forehead support that creates addition contact points between the mask and the user's head. The forehead support minimizes the movement of the mask as well as minimizes uncomfortable pressure points of the mask by preventing the mask from pushing too strongly against the user's nose and/or facial region.
Forehead supports typically have attached thereto a soft comfortable patient-contacting forehead pad. Forehead pads are generally constructed from soft materials, such as silicone, in contrast to the forehead support, which is generally rigid. One form of prior art forehead pad is disclosed in U.S. Pat. No. 6,119,693, the contents of which are hereby incorporated by reference in their entirety.
A problem with existing forehead pads is the mechanism by which the pad is connected to forehead support. The pad must be secured in such a way so as to be easy to insert and remove, but not be unintentionally dislodged. Furthermore, regardless of the relative proximity between the forehead support/pad and the mask frame, there should be no sharp edges against which the user's face can make contact, leading to further discomfort.
One form of known forehead pad is used on the AIR PILOT mask, manufactured by MPV, Truma, Germany, shown in FIGS. 50 to 57. This forehead pad includes a stalk adapted to be pulled through a hole on an arm of a forehead support. The pad also includes two rows of three slots adapted to engage with two rows of three teeth which project rearwardly from the arm of the forehead support. Problems with this type of forehead pad include: (i) it is difficult to assemble; (ii) it is difficult to remove; (iii) it may become dislodged during the night and present sharp teeth to the forehead of a patient; (iv) it has a vague assembly which makes it difficult to know when it is in the correct position; (v) its construction leads to regions of high pressure under the teeth; and (vi) it presents an edge to the forehead of a patient when rocked at an angle.
A further problem with existing forehead pads is that they can lead to uneven pressure on the user's forehead, leading to discomfort and marks on the face. For example, one form of known forehead pad includes a patient contacting surface and a pair of reinforcing struts, as shown in FIGS. 16 to 17. During use, the pad is subject to a compressing force that can lead to pressure points, lines or ridges on the patient contacting surface in the region where the reinforcing struts join it. This can lead to uneven pressure on the user's forehead. The use of existing forehead pads also results in sweating by the user.
Another problem with a known form of forehead support is the mechanism for engaging the forehead pad with the forehead support. The forehead support includes a pair of rigid L-shaped catches c adapted to slidably engage with a recess in the forehead pad, as shown in FIGS. 18 to 20. A problem can arise if a pad is not in position when the forehead support is in use: the catch may abut against the forehead of a user. This can lead to discomfort and marking of the forehead.
Therefore, there exists a need in the art for a forehead pad that overcomes the problems listed above.